1. DO NOW Open your notebook, ready to take notes.
Answer this question in your notebook: What is the difference between an element and a compound?
Reminder: Isotopes Lab due Friday

2. ELEMENTS, COMPOUNDS, AND MIXTURES

3. An element is a substance composed of a single kind of atom

4. Example: Aluminum

5. - Atoms are the basic particles
of an element.
Different elements have different properties because their atoms are different

6. When atoms combine they form a chemical bond, a force or attraction between two atoms.
In most cases, atoms combine to form larger particles called molecules.

7. Example: A molecule of water consists of an oxygen atom chemically combined to two hydrogen atoms.

8. - Compound: 2 or more elements chemically combined in a set ratio

9. A compound may be represented by a chemical formula, which shows the elements in the compound and the ratio of the atoms.
Example:
Carbon Dioxide

10. When elements are chemically combined, they form compounds having properties that are different from those of the uncombined elements!

11. Example: A snail’s shell is composed of calcium, carbon, and oxygen

12. Number of Elements H2O  Made of two different elements
Example:
H2O  Made of two different elements
Hydrogen, Oxygen
C6H12O6  How many different elements?
Three! Carbon, Hydrogen, Oxygen

13. The subscript is the number written to the right of a chemical symbol and slightly below it.